1. Field
A method of fabricating an ultra-small nanowire and a semiconductor device having an ultra-narrow channel formed in the nanowire.
2. Description of the Related Art
Advances in semiconductor devices and the ongoing quest for miniaturization of the semiconductor devices lead to a demand for a better fabrication process for nanoscale structures. Semiconductor devices are being made on nanoscale structures since smaller devices typically equate to faster switching times, which lead to speedier and better performance. Devices based upon nanoscale structures having ultra-small dimensions are thus a natural progression of semiconductor device scaling. For example, devices have been made on a semiconductor nanoscale structures generally known as “nanowire.” A nanowire is referred to as a semiconductor (e.g., silicon) structure having dimensions in the order of nanometers. Current methods of fabricating nanowires include photolithography and vapor liquid solid epitaxy deposition.
In photolithography, a thin layer of semiconductor material (e.g., silicon) is deposited on a substrate and then patterned to form nanowires on the substrate. In vapor liquid solid epitaxy deposition, metal colloids (e.g., gold or nickel) in nano-dimensions are exposed to a silicon source gas (e.g. silane) under high temperature. Silicon is then decomposed and grown on the colloids forming silicon nanowires. The silicon nanowires are removed from the colloids and are deposited on a substrate. Under both methods, the dimensions of the nanowires are difficult to control especially for dimensions less than 5 nm.
In addition, in devices made on nanowires, the device channels are extremely narrow. Extremely narrow channels (<10 nm) can exhibit 1-D device transport which promises higher mobility and possible ballistic transport to improve device performance. However, methods of making these ultra-small channels in a controllable way are not yet currently compatible with high-volume manufacturing processes.